Chinese Prime Minister Zhu Rongji Thursday denied knowledge of espionage or attempts by China's government to aid President Clinton's re-election campaign with cash in 1996.

But he said China's government would cooperate with U.S. investigations on both counts.

"I would like to make a very solemn statement here that I have no knowledge whatsoever of any charge, of any allegation, of espionage or the theft of nuclear technologies," Mr. Zhu said, as translated by an interpreter, at a 90-minute joint news conference with Mr. Clinton.

"It is not the policy of China to steal so-called 'military secrets' from the United States," he added.

During an often-dour news conference -- one of the longest of Mr. Clinton's presidency -- Mr. Zhu also defiantly dismissed criticism of China's human rights record, calling it interference in China's internal affairs.

Pointing to Abraham Lincoln's conduct in the Civil War, the Chinese leader also refused to rule out use of force to reunite Taiwan with the mainland.

"Abraham Lincoln, in order to maintain the unity of the United States and oppose independence of the southern part, he had resorted to the use of force and fought a war for that -- for maintaining the unity of the United States," he said.

"The Chinese government has repeatedly stated that we strive for a peaceful reunification of the motherland," but "if we were to make such a pledge," he said, "then I'm afraid Taiwan would be in a perpetual state of separation from the motherland."

The news conference came after a long day of tough talks between leaders of nations with strained relations over trade, Taiwan, human rights and national security.

Mr. Clinton and Mr. Zhu, the first prime minister of China to visit the United States since 1984, failed to reach an agreement that would grant China entrance to the World Trade Organization. But Mr. Clinton and Mr. Zhu pledged to complete the negotiations by this fall.

The meeting came amid reports that China's military intelligence tried to boost Mr. Clinton's re-election bid with campaign cash in 1996.

The Washington Times reported this week that in grand jury testimony, Johnny Chung, a former Democratic fund-raiser, has for the first time linked Charles Yah Lin Trie and John Huang directly to a massive fund-raising offensive financed by Chinese military intelligence to help Mr. Clinton win re-election.

In the wake of reports that China stole U.S. nuclear warhead designs in the 1980s, the New York Times reported Thursday that Beijing also obtained U.S. weapons secrets in 1995 to improve its neutron bomb.

This week, Mr. Clinton tried to blunt Republican complaints about his China engagement policy, dismissing as "caricature" the view that China is a threat to the United States.

At least publicly, Mr. Clinton gave Mr. Zhu's denials the benefit of the doubt Thursday.

"You know, China is a big country with a big government, and I can only say that America is a big country with a big government, and occasionally things happen in this government that I don't know about," Mr. Clinton said.

Mr. Zhu and Mr. Clinton met a standing-room-only crowd of reporters in the sweltering Presidential Hall at the Old Executive Office Building. The East Room of the White House was being readied for last night's state dinner.

While he spoke in subdued tones, Mr. Clinton criticized China for its human rights abuses.

"We disagree, of course, on the meaning and reach of human rights," Mr. Clinton said.

"It is troubling that in the past year China has taken some steps backwards on human rights in arresting people basically for seeking to express their political views. I also regret that more progress has not been made to open a dialogue with the Dalai Lama," he said.

Mr. Clinton said "the American people and, indeed, people all around the world believe that all persons are entitled to fundamental freedoms that include freedom of speech, religion and association."

Mr. Zhu decried a draft resolution by the Human Rights Commission that faults China's human rights abuses.

"I not only regard that as unfair, but also take it as an interference in China's internal affairs," he said.

Mr. Zhu said that "in terms of the freedom of speech and freedom of press," China "has made very great progress."

Every country has its own approach in improving its human rights, the Chinese leader said, scolding that "one should not be too impatient."

Mr. Zhu, who took office a year ago, said he was reluctant to make the visit because of what he called the "anti-China" atmosphere in the United States.

He said a congressional delegation from the United States, which visited China in recent weeks, persuaded him to make the visit.

He suggested that differences over the WTO are "not very significant," but are being held up by "the political atmosphere" in the United States.

In Lafayette Square and on Pennsylvania Avenue, more than 200 protesters with the International Campaign for Tibet chanted slogans such as: "Free Tibet Before Free Trade" and "Clinton, Albright, just say no! Most-favored-nation has got to go!"

The U.S. and China delegations did sign lesser trade agreements on civil aviation, opening China's markets to U.S. exports of citrus, meat products and wheat, and expanding civil aviation, and assuring that China's government agencies will use only licensed computer software.

Early Thursday, Mr. Clinton welcomed Mr. Zhu in a ceremony on the South Lawn of the White House that featured a 19-gun salute.

Mr. Clinton also acknowledged the nation's troubled diplomacy.

"We have done great things together, and we have disagreed on many occasions," Mr. Clinton said.

"For over two decades in this century, we had no conversations at all. That was not healthy for either China or the United States."

Mr. Zhu said through an interpreter that he brings greetings "from the 1.2 billion Chinese people to the great American people."

He added that "a close cooperation between our two countries can lay a solid foundation for maintaining world peace and preventing war and conflicts."